Precognitive dreams, telepathic interactions, poltergeist-type incidents, and the like, can be disturbing to people who experience them. Some parapsychologists recognize the need to address such anomalies in a counselling context, seeking to explain them to the experient and alleviate any distress they cause. This relatively new field is called clinical parapsychology.
Introduction
Surveys carried out by parapsychologists since the late nineteenth century have shown a high prevalence of apparently paranormal experiences in the general population.1 In Western culture these are often treated as a mental health issue, dismissed as a pathological disturbance of the mind.2 Unable to get help from the medical profession, people who seek to understand these experiences may instead turn to alternative worldviews such as spirituality and transpersonal psychology, or, less positively, start to imagine they possess superhuman occult powers.3 Clinical parapsychology has developed in recent years as a means to provide appropriate help to experients in a neutral, non-idological setting.
Individuals who look to parapsychologists for advice may have specific motives: to be recognized as exceptional; to stop disturbances that are frightening and appear to have a supernatural origin (for instance of the ‘poltergeist’ type); or to to share concerns they dare not discuss with their conventional doctor. However, this requires a change of attitude by parapsychologists, who conventionally are researchers seeking among other things to distinguish genuine paranormal experiences from ordinary experiences interpreted by the individual as paranormal .
The term ‘clinical parapsychology’ was coined in 1948 by Laurence John Bendit, a French psychiatrist, psychoanalyst and theosophist.4 Bendit sought to establish a program which deals with subjective values, unlike academic parapsychology, and which avoids the controls that are normal in controlled laboratory work but which here would disrupt the therapeutic aim. Bendit argued that, acting as a clinician, a parapsychologist should try to help the patient understand the experience without resorting to cross-examination, as would be the case in a scientific context.5
Similarly, Pascal Le Maléfan, a French psychologist and psychoanalyst, argued that clinical parapsychology only works if the intention is to help the patient deal with the experience rather than trying to authenticate it.6 The practitioner simply listens to the patient describe a traumatic ‘abduction’ experience, for instance, without needing to believe (or disbelieve) that it was really caused by extraterrestrials.7
Accordingly, several authors have preferred the neutral term ‘exceptional experiences’ (ExE), as favouring a ‘person-centered’ approach, in which the goal is to understand the experience in subjective terms of its meaning for the individual, rather than as objective evidence of a paranormal process.8
Martina Belz9 and Wolfgang Fach, counsellers at Germany’s Institute of Border Areas of Psychology and Mental Hygiene, expanded this principle to create a systematic phenomenological classification. Here, ExE typically appear as deviations in an individual’s reality model, classified according to two pairs of phenomena.10 One pair refers to experiences that appear to contradict the individual’s sense of self and of the external world. The other refers to the way in which elements of those models are merged or separated above or below ordinary correlations (ranging from coincidence to dissociation phenomena, respectively). This model has since been reinforced by evidence collected by use of the Phenomenology of ExE questionnaire.11
The definition highlights the dynamic aspect of such experiences, which Renaud Evrard refers to as a ‘paradigmatic breakdown’.12 Certain unusual experiences become dissonant with an individual’s worldview, potentially causing anxiety. This dissonance can be weakened by a ‘paradigmatic reframing’,13 in either a reducing or an extending way. The role of the clinical parapsychologist may be defined as aiding this reframing process for a therapeutic and non-ideological purpose.
Recognizing that such counselling does not require a certain belief system, clinical parapsychology is more correctly seen as an aspect of classical psychological counselling than as an application of parapsychology in a clinical setting. Accordingly, Thomas Rabeyron has developed a non-judgmental psychodynamic psychotherapy of ExE based on three main steps: phenomenological exploration, subjective inscription, and subjective integration of the experience.14 Here, the clinician is advised to help patients to formulate and experience their own subjective truth, rather than impose an external idea.15 A further advantage of this approach is that it opens the field to clinicians who may be unconvinced about the existence of paranormal phenomena.16
Counselling Services
Clinical parapsychology practice is generally found in parapsychology research centres,17 and has become increasingly formalized over three decades.18 However, the number of different theoretical and practical frameworks means that it is unlikely to become established as an international profession in the near future.19
Dedicated counselling services are rare. Two are found in Freiburg-im-Breisgau, Germany, and an organized network exists in France (below).
WGFP
Parapsychologische Beratungsstelle (Parapsychological counseling office) of the Wissenschaftlichen Gesellschaft zur Förderung der Parapsychologie (WGFP; Scientific Society for the Advancement of Parapsychology). Led by Walter von Lucadou, PhD in physics and in psychology, this is a professional unit with government support, handling around 3,000 contacts a year, mostly by letter, email and telephone.
The unit specifies an ideology-free approach, with interventions based on the systems theory model of pragmatic information developed by von Lucadou since 1972.20 This practice has produced several academic works in the field.21
IGPP
Beratung und Information für Menschen mit Außergewöhnlichen Erfahrungen’ (Counselling and Information for People with Exceptional Experiences) of the Institut für Grenzgebiete der Psychologie und Psychohygiene (IGPP; Institute for Border Areas of Psychology and Mental Hygiene).
This started with a pilot counseling service, which ran from 1996 for two years at the Institute of Psychology of the Albert Ludwig University of Freiburg.22 It then developed specific tools: telephone-counselling;23 letter or e-mail counselling;24 client-perspective evaluation of the counselling;25 and a documentation system.26 Face-to-face interviews are equally rare as in the WGFP because of the geographic spread of the population. The service is contacted by several hundreds of people each year, mostly by phone, letters or e-mails. It also offers professional training for practitioners wishing to specialize in parapsychological counselling.
CIRCEE
In France, counselling services are offered by the Center for Information, Research and Consultation about Exceptional Experiences (CIRCEE). Originally named SOS-PSEE (Service of Orientation and Support for People Sensibilized to Exceptional Experiences), it was created in 2007 by Renaud Evrard and Thomas Rabeyron within the Institut Métapsychique International, a leading French foundation dedicated to parapsychological research. Clinical psychologists run a consultation service and carry out research in order to achieve a better understanding of these unusual experiences.27
Even more rare are services that cover parapsychological issues in other areas of counselling and psychotherapy, with the necessary empirically-supported standards.28 This kind of counselling could usefully be practised even by therapists who have no explicit interest in parapsychological issues.29
Other Clinical Approaches
Other clinical approaches that have been applied to exceptional experiences are psychoanalytic parapsychology and transpersonal psychotherapy.
Psychoanalytic Parapsychology
The development of psychoanalysis at the end of the nineteenth century offered a potential framework for the integration of anomalous experiences into normal psychology. Sigmund Freud acknowledged the reality of ‘thought-transference’ (telepathy) and came up with hypotheses to explain its emergence in a clinical setting. He did not pursue this, and the concept remained marginal in psychoanalysis.30 Nevertheless, it continued to interest some researchers and practitioners. Devereux’s 1953 anthology Psychoanalysis and the Occult31 contains discussions and case studies about three types of ‘correspondences’ occurring in the clinical setting:
- the same thought arising in the mind of both analyst and patient
- the patient’s thoughts corresponding with external events
- the analyst’s thoughts corresponding with external events
Other psychoanalysts have expanded on Freud’s ideas32 and explored the complex processes involved.33 Some have even contributed to parapsychological research, notably landmark laboratory experiments on telepathic dreams carried out from the late 1960s at the Maimonides Medical Center in New York.34 However, an absence of integration of such research efforts means that knowledge of parapsychological matters has failed to become established within psychoanalysis, and as a result individual practitioners are always discovering the subject afresh. Only recently, the psychoanalytic framework has been applied to other ExE such as out-of-body,35 near-death36, abduction37, and poltergeist experiences.38
Transpersonal Psychotherapy
Transpersonal psychology has developed an amalgam of exceptional and spiritual experiences, termed ‘transpersonal experiences’. The distinction between a pathological mental experience and a spiritual experience that is temporarily destablizing has not been satisfactorily resolved.39 Nevertheless, the ideas of transpersonal psychology have achieved some success, notably the creation of a small category in the 1994 DSM-IV manual (Diagnostic and Statistical Manual of Mental Disorders, the standard handbook of mental health diagnosis) that allows for the existence of non-pathological religious and spiritual experiences.40
Transpersonal psychotherapy tends to focus on the positive aspects of such experiences.41 Here, paranormal interpretations can be comforting and contribute to psychological wellbeing.42 Alternative communities and peer-support groups developed by experiencers have been shown to have many benefits for their members.43
Transpersonal psychotherapy has led to innovations such as an early use of psychedelic drugs, holotropic breathing, and Eastern approaches such as yoga, meditation and shamanism. That opens the prospect of a return to trance-based therapy.44 Attempts are currently being made to assess the efficiency of such therapeutic innovations as the psychomanteum, a darkened chamber of the kind thought to have been used in ancient Greece to facilitate spirit communication.45
Wider Concerns
Although commonly seen as specialized counselling for otherwise inappropriately considered experiences, clinical parapsychology can be considered relevant for the whole mental health field. This calls into question the boundaries of psychopathology: the practitioner requires not only cultural sensibility towards non-Western ways of thinking (animism, Eastern traditions), but also for Western knowledge outside the mainstream, such as parapsychology, spiritism and New Age interests.
Clinical parapsychology also presents a challenge within parapsychology, requiring a redefinition of basic elements of phenomenology and the whole epistemological framework. It can be seen as a clinical counterpart of anomalistic psychology, the research program that attempts to integrate unusual experiences into conventional psychology, by developing new methods and hypotheses. However, anomalistic psychology does not apply in the mental health field: for example, the 2014 book Varieties of Anomalous Experience offers only a few options for clinical practice with people who have exceptional experiences.46
Renaud Evrard
Literature
Atmanspacher, H., & Fach, W. (2013). A structural-phenomenological typology of mind-matter correlations. Journal of Analytical Psychology 58/2, 219-44.
Atmanspacher, H., & Fach, W. (2019). Exceptional experiences of stable and unstable mental states, understood from a dual-aspect point of view. Philosophies 4/7.
Belz, M. (2009a). Außergewöhnliche Erfahrungen [Exceptional experiences]. Göttingen, Germany: Hogrefe.
Belz, M. (2009b). Clinical parapsychology: Today’s implications, tomorrow’s applications. In Utrecht II: Charting the Future of Parapsychology, Proceedings of an International Conference held in Utrecht, The Netherlands, October 16-18, 2008, ed. by C.A. Roe, W. Kramer, & L. Coly, 326-62. New York: Parapsychology Foundation.
Bendit, L.J. (1948). Further contributions on a research program: Dear Professor Rhine [Letter to the editor]. Journal of Parapsychology 12, 224-27.
Bengel, J., & Mischo, J. (1998). Abschlußbericht der Arbeitsgruppe „Beratung und Hilfe für Menschen mit Außergewöhnlichen Erfahrungen“. Rapport de recherché non publié. Psychologisches Institut der Albert-Ludwigs-Universität Freiburg.
Belz-Merk, M., & Fach, W. (2005). Beratung und Hilfe für Menschen mit Außergewöhnlichen Erfahrungen. Psychotherapie, Psychosomatik, Medizinische Psychologie 55, 256-265.
Bradbury, D.A., Stirling, J., Cavill, J., & Parker, A. (2009). Psychosis-like experiences in the general population: An exploratory factor analysis. Personality and Individual Differences 46/7, 729-34.
Cardeña, E., Lynn, S.J., & Krippner, S. (Eds.). (2014). Varieties of Anomalous Experience: Examining the Scientific Evidence (2nd ed.). Washington, DC: American Psychological Association.
Caussié, S., Charlet, O., Evrard R., & Rabeyron, T. (2016). Introducing CIRCEE : A French approach to exceptional experiences. Journal of Exceptional Experiences and Psychology 4/1, 14-16.
Coelho, C., Tierney, I., & Lamont, P. (2008). Contacts by distressed individuals to UK parapsychology and anomalous experience academic research units: A retrospective survey looking to the future. European Journal of Parapsychology 23, 31-59.
Coly, L., & McMahon, J. (ed.) (1993). Psi and Clinical Practice. New York: Parapsychology Foundation.
Devereux, G. (ed.), (1953). Psychoanalysis and the Occult. New York: International University Press.
Evrard, R. (2007). La clinique parapsychologique / La clinica parapsicologica. M@gm@ 5/3.
Evrard, R. (2012a). Clinical practice of anomalous experiences: Roots and paradigms. In Mental Health and Anomalous Experience, ed. by C.D. Murray, 89-106. New York: Nova Science Publishers.
Evrard, R. (2012b). Spirituality as an anti-psychopathological discourse on exceptional experiences. In Handbook of Spirituality: Belief Systems, Societal Impact and Roles in Coping, ed. by C.A. Stark & D.C. Bonner, 279-89. New York: Nova Science Publishers.
Evrard, R. (2013). What should psychology do with exceptional experiences? Journal of Exceptional Experiences and Psychology 1/2, 27-33.
Evrard, R. (2014). Folie et Paranormal. Vers une Clinique des Expériences Exceptionnelles. Rennes: Presses Universitaires de Rennes.
Evrard, R. (2015). The paradigmatic breakdown: A model to define the ExE dynamics. Journal of Exceptional Experiences 3/1, 19-29.
Evrard, R. (2016). What is clinical parapsychology? Parapsychologists’ discussions between 1985 and 1995. Journal of Exceptional Experiences and Psychology 4/1, 20-36.
Evrard, R., & Le Maléfan, P. (2010). Pression des nouvelles mentalités sur le DSM - le cas des problèmes religieux ou spirituels. L’Evolution Psychiatrique 75/4, 549-63.
Evrard, R., Toutain, C., Glazier, J.W., & Le Maléfan, P. (2019). The energy of despair: do near-death experiences have a evolutionary value? Psychology of Consciousness: Theory, Research, and Practice 6/2, 184-99.
Fach, W. (2011). Phenomenological aspects of complementarity and entanglement in exceptional human experiences (ExE). Axiomathes 21/2), 233-47.
Fach, W., Atmanspacher, H., Landolt, K, Wyss, T., & Rössler, W. (2013). A comparative study of exceptional experiences of clients seeking advice and of subjects in an ordinary population. Frontiers in Psychology. doi : 10.3389/fpsyg.2013.00065
Fangmeier, R. (1999). Entwicklung eines Konzepts für telefonische Beratung im Bereich der Beratung für Menschen mit Außergewöhnlichen Erfahrungen. Unpublished master thesis in psychology, Albert-Ludwig University of Freiburg, Freiburg-im-Breisgau, Germany.
Gebhardt, C. (2000). Brief und E-Mail als Medium von Beratung und Therapie: Analyse der Briefe und E-Mails von ratsuchenden Menschen mit Außergewöhnlichen Erfahrungen. Unpublished master thesis in psychology, Albert-Ludwig University of Freiburg, Freiburg-im-Breisgau, Germany.
Greyson, B. (1977). Telepathy in mental illness: Deluge or delusion? Journal of Nervous and Mental Disease 165, 184-200.
Gurney, E, Myers, F.W.H., & Podmore, F. (1886). Phantasms of the Living (2 vols.). London: Trübner.
Hastings, A. (1983). A counselling approach to parapsychological experience. Journal of Transpersonal Psychology 15/2, 143-67.
Hastings, A., Hutton, M., Braud, W., Bennett, C., Berk, I., Boynton, T., … Steinbach-Humphrey, S. (2002). Psychomanteum research: Experiences and effects on bereavement. OMEGA - Journal of Death and Dying 45/3, 211-28.
Henry, J. (Ed., 2005). Parapsychology: Research on Exceptional Experiences. London: Routledge.
Hofer, J.M. (2018). Sprache der Transzendenzerfahrungen: Die Briefsammlung der Parapsychologischen Beratungsstelle in Freiburg i.B. Bielefeld: transcript.
Irwin, H. J., & Watt, C. A. (2007). An Introduction to Parapsychology (5th ed.). Jefferson, North Carolina, USA: McFarland.
Irwin, H. J., Dagnall, N., & Drinkwater, K. (2013). Parapsychological experience as anomalous experience plus paranormal attribution: A questionnaire based on a new approach to measurement. Journal of Parapsychology 77/1, 39-53.
Kohls, N., & Walach, H. (2008). Lack of spiritual practice: Aan important risk factor for suffering from distress. Newsletter 25. Spirituality and Psychiatry Special Interest Group, Royal College of Psychiatrists.
Kramer, W.H, Bauer, E., & Hövelmann, G.H. (2012). Perspectives of Clinical Parapsychology: An Introductory Reader. Bunnik: Stichting HJBF. Utrecht, The Netherlands: HJBF.
Kühn, S. (2001). Entwicklung eines Erhebungsinstruments zur Evaluation psychologischer Beratung aus Sicht der Klienten. Unpublished master thesis in psychology, Albert-Ludwig University of Freiburg, Freiburg-im-Breisgau, Germany.
Landolt, K., Wittwer, A., Wyss, T., Unterassner, L., Fach, W., Krummenacher, P., Brugger, P., Haker, H., Kawohl, W., Schubiger, P.A., Folkers, G., & Rössler, W. (2014). Help-seeking in people with exceptional experiences: results from a general population sample. Frontiers in Public Health. doi : 10.3389/fpubh.2014.00051
Lange, R., Ross, R. M., Dagnall, N., Irwin, H. J., Houran, J., & Drinkwater, K. (2019). Anomalous experiences and paranormal attributions: Psychometric challenges in studying their measurement and relationship. Psychology of Consciousness: Theory, Research, and Practice 6/4, 346-58.
Le Maléfan, P. (1990). Parapsychologie et psychologie clinique: Quels rapports? Quels apports? Revue Française de Psychotronique 3/2, 61-67.
Lucadou, W. (2015). The Model of Pragmatic Information (MPI). In Extrasensory Perception: Support, Skepticism, and Science, vol. 2., Theories and the Future of the Field, ed. by E.C. May, & S. Marwaha (eds.), 221-42). Santa Barbara, California, USA: Praeger.
Lucadou, W., & Wald, F. (2014). Extraordinary experiences in its cultural and theoretical context. International Review of Psychiatry 26/3, 324-34.
Maleval, J.-C., & Charraud, N. (2003). The "alien abduction" syndrome. In Psychoanalysis and the Paranormal: Lands of Darkness ed. by N. Totton, 129-42. London-New York: Karnac.
Mathijsen, F. (2019). Les Jeunes, le Cerveau et le Paranormal. Le syndrome du Bernard-L’ermite. Louvain-la-Neuve: Presses Universitaires de Louvain.
Mayer, G., & Gründer, R. (2011). The importance of extraordinary experiences for adopting heterodox beliefs or an alternative religious worldview. Journal of the Society for Psychical Research 75 1, 14-25.
Nemeth, M. (1987). The practice of clinical parapsychology: Ethical considerations and training issues. In Research in Parapsychology 1986, ed. by D.H. Weiner & R.D. Nelson, 175. Jefferson, North Carolina, USA & London: Scarecrow Press.
Palmer, G., & Braud, W. (2002). Exceptional human experiences, disclosure, and a more inclusive view of physical, psychological, and spiritual well-being. Journal of Transpersonal Psychology 34/1, 29-61.
Palmer, G. (1999). Disclosure and assimilation of exceptional human experiences: Meaningful, transformative, and spiritual aspects. Unpublished doctoral thesis in psychology. Palo Alto, California, USA: Institute of Transpersonal Psychology.
Rabeyron, T. (2018). Clinique des expériences d’abduction: trauma, clivage et logiques de l’originaire. L’Evolution Psychiatrique 83/2, 355-79.
Rabeyron, T. (2020). Clinique des Expériences Exceptionnelles. Paris: Dunod.
Rabeyron, T., Evrard, R., & Massicotte, C. (2020). Psychoanalysts and the sour apple: Thought-transference in historical and contemporary psychoanalysis. Contemporary Psychoanalysis 56/4, 612-52.
Rabeyron, T., Evrard, R., & Massicotte, C. (2021). Psychoanalysis and telepathic processes. Journal of the American Psychoanalytical Association 69/3, 535-71.
Rabeyron, T., (2022). When the truth is out There: Counseling people who report anomalous experiences. Frontiers in Psychology 12, 693-707.
Rabeyron, T., & Loose, T. (2015). Anomalous experiences, trauma and symbolization at the frontiers between neurosciences and psychoanalysis. Frontiers in Psychoanalysis and Neuropsychoanalysis 6, 19-26.
Rabeyron, T., & Caussié, S. (2016). Clinical aspects of out-of-body experiences: Trauma, reflexivity and symbolization. L’Evolution Psychiatrique 81/4, e53-e71.
Reichbart, R. (2019). The Paranormal Surrounds Us. Psychic Phenomena in Literature, Culture and Psychoanalysis. Jefferson, North California, USA: McFarland & Cie.
Roe, C. (2020). Clinical parapsychology: The interface between anomalous experiences and psychological wellbeing. In Spirituality and Wellbeing. Interdisciplinary Approaches to the Study of Religious Experience and Health, ed. by B.E. Schmidt & J. Leonardi, 44-63. Sheffield: Equinox Publishing Ltd.
Rogo, D.S. (1975). Psi and psychosis: A review of the experimental evidence. Journal of Parapsychology 39, 120-28.
Roll, W.G. (1986). Roundtable: Clinical parapsychology. In Research in Parapsychology 1985 ed. by D.H. Weiner & D.I. Radin,168-77. Jefferson, North Carolina, USA & London: Scarecrow Press.
Roxburgh, E.C., & Evenden, R.E. (2016a). ‘They daren’t tell people’: Therapists’ experiences of working with clients who report anomalous experiences. European Journal of Psychotherapy and Counseling. DOI: 10.1080/13642537.2016.1170059.
Roxburgh, E.C., & Evenden, R.E. (2016b). ‘Most people think you’re a fruit loop’: Clients’ experiences of seeking support for anomalous experiences. Counseling & Psychotherapy Research. DOI: 10.1002/capr.12077.
Sagher, A., Butzer, B., & Wahbeh, H. (2019). The characteristics of exceptional human experiences. Journal of Consciousness Studies 26(11-12), 203-237.
Schetsche, M. (2003). Soziale Kontrolle durch Pathologisierung? Konstruktion und Dekonstruktion‚ außergewöhnlicher Erfahrungen’ in der Psychologie. In Grenzenlose Konstruktivität? Standortbestimmung und Zukunftsperspektiven konstruktivistischer Theorien abweichenden Verhaltens ed. by B. Menzel & K. Ratzke, K., 141-60. Opladen: Leske/Budrich.
Schofield, K., & Claridge, G. (2007). Paranormal experiences and mental health: Schizotypy as an underlying factor. Personality and Individual Differences 43/7, 1908-16.
Si Ahmed, D. (2014). Pour une Psychanalyse des Expériences Exceptionnelles. Comment Penser le Paranormal. Paris: L’Harmattan.
Sidgwick, H., Johnson, A., Myers, F.W.H., Podmore, F., & Sidgwick, E.M (1894). Report on the census of hallucinations. Proceedings of the Society for Psychical Research 10, 25-422.
Tremmel, M. (2014). Clarification of terms and concepts defining parapsychology and related disciplines: Comments on Mathijsen (2009, 2013), Abrassart (2013), and Evrard (2013). Journal of Exceptional Experiences and Psychology 2/1, 21-40.
Ullman, M., Krippner, S., & Vaughan, A. (1977). La Télépathie Par le Rêve. Paris: Tchou.
Walsh, R.N., & Vaughan, F. (1980). Beyond Ego: Transpersonal Dimensions in Psychology. Los Angeles: J.P. Tarcher.
White, R.A. (1994). Exceptional Human Experiences: Background Papers I. New Bern, North Carolina, USA: EHE Network.
Zahradnik, F. (2007). Irritation der Wirklichkeit. Eine qualitative und quantitative. Analyse der Briefsammlung der Parapsychologischen Beratungsstelle in Freiburg. PhD in sociology, University of Konstanz.
Endnotes
- 1. E.g., Gurney et al. (1886) and Sidgwick et al. (1894).
- 2. Bradbury et al. (2009); Schetsche (2003).
- 3. Evrard (2012b); Mayer & Gründer (2011).
- 4. Tremmel (2014).
- 5. Bendit (1948), 225.
- 6. Le Maléfan (1990), 64.
- 7. Rabeyron (2018).
- 8. White (1994).
- 9. Belz (2009a).
- 10. Fach (2011); Atmanspacher & Fach (2013, 2019).
- 11. PAGE-R and PAGE-R-2; Fach et al. (2013); Atmanspacher & Fach (2019).
- 12. Evrard (2015).
- 13. Mathijsen (2019).
- 14. Rabeyron (2022).
- 15. Rabeyron (2020).
- 16. Belz (2009b), 355.
- 17. Coelho, Lamont & Tierney (2008).
- 18. Coly & McMahon (1993); Kramer, Bauer & Hövelmann (2012).
- 19. Evrard (2007).
- 20. Von Lucadou (2015).
- 21. Zaradhnik (2007); von Lucadou & Wald, 2014; Hofer, 2018).
- 22. Bengel & Mischo, 1998).
- 23. Fangmeier (1999).
- 24. Gebhardt (2000).
- 25. Kühn (2001).
- 26. Fach (2011; Belz-Merk & Fach (2005).
- 27. Caussié, Charlet, & Evrard, & Rabeyron (2016).
- 28. Belz (2009b), 326.
- 29. Roxburgh & Evenden (2016a, 2016b).
- 30. Reichbart (2019).
- 31. Devereux (1953).
- 32. Rabeyron, Evrard & Massicotte (2020).
- 33. Rabeyron, Evrard & Massicotte (2021).
- 34. Ullman, Krippner, & Vaughan (1977).
- 35. Rabeyron & Caussié (2016).
- 36. Evrard et al. (2019).
- 37. Rabeyron (2018); Maleval & Charraud (2003).
- 38. Si Ahmed (2014).
- 39. Kohls & Walach (2008).
- 40. Evrard & Le Maléfan (2010).
- 41. Roe (2020).
- 42. Schofield & Claridge (2007).
- 43. Palmer (1999; Palmer & Braud (2002).
- 44. Walsh & Vaughan (1984).
- 45. Hastings et al. (2002).
- 46. Cardeña et al. (2014).